Paolo Saggese

Istituto Nazionale di Fisica Nucleare, Sezione di Milano, CTER

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Papers by Paolo Saggese

$Research paper thumbnail of JUNO Sensitivity on Proton Decay $p\to \bar\nu K^+$ Searches$

JUNO Sensitivity on Proton Decay $p\to \bar\nu K^+$ Searches

HAL (Le Centre pour la Communication Scientifique Directe), Dec 16, 2022

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Study of the primary cosmic ray composition around 1000 TeV with EAS-TOP and MACRO

Nuclear Physics B - Proceedings Supplements, 1996

Damping signatures at JUNO, a medium-baseline reactor neutrino oscillation experiment

Journal of High Energy Physics

We study damping signatures at the Jiangmen Underground Neutrino Observatory (JUNO), a medium-bas... more We study damping signatures at the Jiangmen Underground Neutrino Observatory (JUNO), a medium-baseline reactor neutrino oscillation experiment. These damping signatures are motivated by various new physics models, including quantum decoherence, ν3 decay, neutrino absorption, and wave packet decoherence. The phenomenological effects of these models can be characterized by exponential damping factors at the probability level. We assess how well JUNO can constrain these damping parameters and how to disentangle these different damping signatures at JUNO. Compared to current experimental limits, JUNO can significantly improve the limits on τ3/m3 in the ν3 decay model, the width of the neutrino wave packet σx, and the intrinsic relative dispersion of neutrino momentum σrel.

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The DarkSide program at LNGS

Le Centre pour la Communication Scientifique Directe - HAL - Université Paris Descartes, Mar 19, 2016

(The DarkSide Collaboration) The DarkSide program at Laboratori Nazionali del Gran Sasso aims to ... more (The DarkSide Collaboration) The DarkSide program at Laboratori Nazionali del Gran Sasso aims to perform background-free WIMP searches using double phase liquid argon time projection chambers, with the ultimate goal of covering all parameters down to the so-called neutrino floor. One of the distinct features of the program is the use of underground argon with has a reduced content of the $radioactive^{39}$ Ar compared to atmospheric argon. The DarkSide Collaboration is currently operating the DarkSide-50 experiment, the first such WIMP detector using underground argon, resulting in the best WIMP limits obtained with argon. The results obtained with DarkSide-50 and the plans for the next steps of the DarkSide program, the 20 t fiducial mass DarkSide-20k detector and the 200 t fiducial Argo, are reviewed in this proceedings

TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution

arXiv: Instrumentation and Detectors, 2020

The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a satellite experiment of t... more The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A ton-level liquid scintillator detector will be placed at about 30 m from a core of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be measured with sub-percent energy resolution, to provide a reference spectrum for future reactor neutrino experiments, and to provide a benchmark measurement to test nuclear databases. A spherical acrylic vessel containing 2.8 ton gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full coverage. The photoelectron yield is about 4500 per MeV, an order higher than any existing large-scale liquid scintillator detectors. The detector operates at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The detector will measure about 2000 reactor antineutrinos per day, and is de...

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Optimization of the JUNO liquid scintillator composition using a Daya Bay antineutrino detector

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2021

To maximize the light yield of the liquid scintillator (LS) for the Jiangmen Underground Neutrino... more To maximize the light yield of the liquid scintillator (LS) for the Jiangmen Underground Neutrino Observatory (JUNO), a 20 t LS sample was produced in a pilot plant at Daya Bay. The optical properties of the new LS in various compositions were studied by replacing the gadolinium-loaded LS in one antineutrino detector. The concentrations of the fluor, PPO, and the wavelength shifter, bis-MSB, were increased in 12 steps from 0.5 g/L and <0.01 mg/L to 4 g/L and 13 mg/L, respectively. The numbers of total detected photoelectrons suggest that, with the optically purified solvent, the bis-MSB concentration does not need to be more than 4 mg/L. To bridge the one order of magnitude in the detector size difference between Daya Bay and JUNO, the Daya Bay data were used to tune the parameters of a newly developed optical model. Then, the model and tuned parameters were used in the JUNO simulation. This enabled to determine the optimal composition for the JUNO LS: purified solvent LAB with 2.5 g/L PPO, and 1 to 4 mg/L bis-MSB.

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JUNO physics and detector

Progress in Particle and Nuclear Physics, 2021

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector in... more The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector in a laboratory at 700-m underground. An excellent energy resolution and a large fiducial volume offer exciting opportunities for addressing many important topics in neutrino and astroparticle physics. With six years of data, the neutrino mass ordering can be determined at a 3-4σ significance and the neutrino oscillation parameters sin 2 θ 12 , ∆m 2 21 , and |∆m 2 32 | can be measured to a precision of 0.6% or better, by detecting reactor antineutrinos from the Taishan and Yangjiang nuclear power plants. With ten years of data, neutrinos from all past core-collapse supernovae could be observed at a 3σ significance; a lower limit of the proton lifetime, 8.34 × 10 33 years (90% C.L.), can be set by searching for p →νK + ; detection of solar neutrinos would shed new light on the solar metallicity problem and examine the vacuum-matter transition region. A typical core-collapse supernova at a distance of 10 kpc would lead to ∼ 5000 inverse-beta-decay events and ∼ 2000 (300) all-flavor neutrino-proton (electron) elastic scattering events in JUNO. Geoneutrinos can be detected with a rate of ∼ 400 events per year. Construction of the detector is very challenging. In this review, we summarize the final design of the JUNO detector and the key R&D achievements, following the Conceptual Design Report in 2015 [2]. All 20-inch PMTs have been procured and tested. The average photon detection efficiency is 28.9% for the 15,000 MCP PMTs and 28.1% for the 5,000 dynode PMTs, higher than the JUNO requirement of 27%. Together with the > 20 m attenuation length of the liquid scintillator achieved in a 20-ton pilot purification test and the > 96% transparency of the acrylic panel, we expect a yield of 1345 photoelectrons per MeV and an effective relative energy resolution of 3.02%/ E(MeV) in simulations [3]. To maintain the high performance, the underwater electronics is designed to have a loss rate < 0.5% in six years. With degassing membranes and a micro-bubble system, the radon concentration in the 35 kton water pool could be lowered to < 10 mBq/m 3. Acrylic panels of radiopurity < 0.5 ppt U/Th for the 35.4-m diameter liquid scintillator vessel are produced with a dedicated production line. The 20 kton liquid scintillator will be purified onsite with Alumina filtration, distillation, water extraction, and gas stripping. Together with other low background handling, singles in the fiducial volume can be controlled to ∼ 10 Hz. The JUNO experiment also features a double calorimeter system with 25,600 3-inch PMTs, a liquid scintillator testing facility OSIRIS, and a near detector TAO.

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The design and sensitivity of JUNO’s scintillator radiopurity pre-detector OSIRIS

The European Physical Journal C, 2021

The OSIRIS detector is a subsystem of the liquid scintillator filling chain of the JUNO reactor n... more The OSIRIS detector is a subsystem of the liquid scintillator filling chain of the JUNO reactor neutrino experiment. Its purpose is to validate the radiopurity of the scintillator to assure that all components of the JUNO scintillator system work to specifications and only neutrino-grade scintillator is filled into the JUNO Central Detector. The aspired sensitivity level of $$10^{-16}\hbox { g/g}$$ 10 - 16 g/g of $$^{238}\hbox {U}$$ 238 U and $$^{232}\hbox {Th}$$ 232 Th requires a large ($$\sim 20\,\hbox {m}^3$$ ∼ 20 m 3 ) detection volume and ultralow background levels. The present paper reports on the design and major components of the OSIRIS detector, the detector simulation as well as the measuring strategies foreseen and the sensitivity levels to U/Th that can be reached in this setup.

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Feasibility and physics potential of detecting 8B solar neutrinos at JUNO *

Chinese Physics C, 2021

The Jiangmen Underground Neutrino Observatory (JUNO) features a 20 kt multi-purpose underground l... more The Jiangmen Underground Neutrino Observatory (JUNO) features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector. Some of JUNO's features make it an excellent location for B solar neutrino measurements, such as its low-energy threshold, high energy resolution compared with water Cherenkov detectors, and much larger target mass compared with previous liquid scintillator detectors. In this paper, we present a comprehensive assessment of JUNO's potential for detecting B solar neutrinos via the neutrino-electron elastic scattering process. A reduced 2 MeV threshold for the recoil electron energy is found to be achievable, assuming that the intrinsic radioactive background U and Th in the liquid scintillator can be controlled to 10 g/g. With ten years of data acquisition, approximately 60,000 signal and 30,000 background events are expected. This large sample will enable an examination of the distortion of the recoil electron spectrum that is domina...

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The DarkSide veto: muon and neutron detectors

L. Pagani(), P. Agnes(), T. Alexander(), A. Alton(), K. Arisaka(), H. O. Back(), B. Baldin(), K. ... more L. Pagani(), P. Agnes(), T. Alexander(), A. Alton(), K. Arisaka(), H. O. Back(), B. Baldin(), K. Biery(), G. Bonfini(), M. Bossa(), A. Brigatti(), J. Brodsky(), F. Budano(), L. Cadonati(), F. Calaprice(), N. Canci(), A. Candela(), H. Cao(), M. Cariello(), P. Cavalcante(), A. Chavarria(), A. Chepurnov(), A. G. Cocco(), D. D’Angelo(), M. D’Incecco(), S. Davini(), M. De Deo(), A. Derbin(), A. Devoto(), F. Di Eusanio(), G. Di Pietro(), E. Edkins(), A. Empl(), A. Fan(), G. Fiorillo(), K. Fomenko(), G. Forster(), D. Franco(), F. Gabriele(), C. Galbiati(), A. Goretti(), L. Grandi(), M. Gromov(), M. Y. Guan(), Y. Guardincerri(), B. Hackett(), K. Herner(), P. Humble(), E. V. Hungerford(), Al. Ianni(), An. Ianni(), C. Jollet(), K. Keeter(), C. Kendziora(), S. Kidner(35)(†), V. Kobychev(), G. Koh(), D. Korablev(), G. Korga(), A. Kurlej(), P. X. Li(), P. Lombardi(), C. Love(), L. Ludhova(), S. Luitz(), Y. Q. Ma(), I. Machulin()(), A. Mandarano(), S. Mari(), J. Maricic(), L. Marini(), C. J. Mart...

The DarkSide project

Journal of Instrumentation, 2016

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Results from the first use of low radioactivity argon in a dark matter search

Liquid argon is a bright scintillator with potent particle identification properties, making it a... more Liquid argon is a bright scintillator with potent particle identification properties, making it an attractive target for direct-detection dark matter searches. The DarkSide-50 dark matter search here reports the first WIMP search results obtained using a target of low-radioactivity argon. DarkSide-50 is a dark matter detector, using two-phase liquid argon time projection chamber, located at the Laboratori Nazionali del Gran Sasso. The underground argon is shown to contain Ar-39 at a level reduced by a factor (1.4 +- 0.2) x 10^3 relative to atmospheric argon. We report a background-free null result from (2616 +- 43) kg d of data, accumulated over 70.9 live-days. When combined with our previous search using an atmospheric argon, the 90 % C.L. upper limit on the WIMP-nucleon spin-independent cross section based on zero events found in the WIMP search regions, is 2.0 x 10^-44 cm^2 (8.6 x 10^-44 cm^2, 8.0 x 10^-43 cm^2) for a WIMP mass of 100 GeV/c^2 (1 TeV/c^2 , 10 TeV/c^2).

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First Results from the DarkSide-50 Dark Matter Experiment at Laboratori Nazionali del Gran Sasso

We report the first results of DarkSide-50, a direct search for dark matter operating in the unde... more We report the first results of DarkSide-50, a direct search for dark matter operating in the underground Laboratori Nazionali del Gran Sasso (LNGS) and searching for the rare nuclear recoils possibly induced by weakly interacting massive particles (WIMPs). The dark matter detector is a Liquid Argon Time Projection Chamber with a (46.4+-0.7) kg active mass, operated inside a 30 t organic liquid scintillator neutron veto, which is in turn installed at the center of a 1 kt water Cherenkov veto for the residual flux of cosmic rays. We report here the null results of a dark matter search for a (1422+-67) kg d exposure with an atmospheric argon fill. This is the most sensitive dark matter search performed with an argon target, corresponding to a 90% CL upper limit on the WIMP-nucleon spin-independent cross section of 6.1x10^-44 cm^2 for a WIMP mass of 100 GeV/c^2.

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$Research paper thumbnail of $^{222}$Rn contamination mechanisms on acrylic surfaces$

$^{222}$Rn contamination mechanisms on acrylic surfaces

arXiv: Instrumentation and Detectors, 2019

In this work, the $^{222}$Rn contamination mechanisms on acrylic surfaces have been investigated.... more In this work, the $^{222}$Rn contamination mechanisms on acrylic surfaces have been investigated. $^{222}$Rn can represent a significant background source for low-background experiments, and acrylic is a suitable material for detector design thanks to its purity and transparency. Four acrylic samples have been exposed to a $^{222}$Rn rich environment for different time periods, being contaminated by $^{222}$Rn and its progenies. Subsequently, the time evolution of radiocontaminants activity on the samples has been evaluated with $\alpha$ and $\gamma$ measurements, highlighting the role of different decay modes in the contamination process. A detailed analysis of the alpha spectra allowed to quantify the implantation depth of the contaminants. Moreover, a study of both $\alpha$ and $\gamma$ measurements pointed out the $^{222}$Rn diffusion inside the samples.

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mbedded readout electronics R & D for the large PMTs in the JUNO xperiment

Jiangmen Underground Neutrino Observatory (JUNO) is a next generation liquid scintillator neutrin... more Jiangmen Underground Neutrino Observatory (JUNO) is a next generation liquid scintillator neutrino experiment under construction phase in South China. Thanks to the anti-neutrinos produced by the nearby nuclear power plants, JUNO will be able to study the neutrino mass hierarchy, one of the open key questions in neutrino physics. One key ingredient for a successful measurement is to use high speed, high resolution sampling electronics located very close to the detector signal. Linearity in the response of the electronics is another ∗ Correspondence to: Universitá di Padova, Dipartimento di Fisica e Astronomia, via F. Marzolo 8, I-35131 Padova. E-mail address: [email protected] (A. Garfagnini). ttps://doi.org/10.1016/j.nima.2020.164600 eceived 20 June 2020; Received in revised form 30 August 2020; Accepted 1 September 2020 vailable online 19 September 2020 168-9002/© 2020 Elsevier B.V. All rights reserved. M. Bellato, A. Bergnoli, A. Brugnera et al. Nuclear Inst. and Meth...

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The DarkSide direct dark matter search with liquid argon

The DarkSide-50 direct dark matter detector is a liquid argon time projection chamber (TPC) surro... more The DarkSide-50 direct dark matter detector is a liquid argon time projection chamber (TPC) surrounded by a liquid scintillator neutron veto (LSV) and a water Cerenkov muon veto (WCV). Located under 3800 m.w.e. at the Laboratori Nazionali del Gran Sasso, Italy, it is the only direct dark matter experiment currently operating background free. The atmospheric argon target was replaced with argon from underground sources in April, 2015. The level of 39Ar, a β emitter present in atmospheric argon (AAr), has been shown to have been reduced by a factor of (1.4 ± 0.2) x 103. The combined spin-independent WIMP exclusion limit of 2.0 x 10−44 cm2 (mχ = 100 GeV/c2) is currently the best limit on a liquid argon target.

The DarkSide experiment

Nuovo Cimento Della Societa Italiana Di Fisica A-nuclei Particles and Fields, 2017

DarkSide is a dark matter direct search experiment at Laboratori Nazionali del Gran Sasso (LNGS).... more DarkSide is a dark matter direct search experiment at Laboratori Nazionali del Gran Sasso (LNGS). DarkSide is based on the detection of rare nuclear recoils possibly induced by hypothetical dark matter particles, which are supposed to be neutral, massive (m > 10 GeV) and weakly interactive (WIMP). The dark matter detector is a two-phase time projection chamber (TPC) filled with ultra-pure liquid argon. The TPC is placed inside a muon and a neutron active vetoes to suppress the background. Using argon as active target has many advantages, the key features are the strong discriminant power between nuclear and electron recoils, the spatial reconstruction and easy scalability to multi-tons size. At the moment DarkSide-50 is filled with ultra-pure argon, extracted from underground sources, and from April 2015 it is taking data in its final configuration. When combined with the preceding search with an atmospheric argon target, it is possible to set a 90% CL upper limit on the WIMP-nuc...

Current status of the dark matter experiment DarkSide-50

Il Nuovo Cimento C, 2015

DarkSide-50 is a dark matter direct search experiment at LNGS, searching for rare nuclear recoils... more DarkSide-50 is a dark matter direct search experiment at LNGS, searching for rare nuclear recoils possibly induced by WIMPs. It has two nested vetoes and a dual phase liquid argon TPC as dark matter detector. Key features of this experiment are the use of underground argon as radio-pure target and of muon and neutron active vetoes to suppress the background. The first data-taking campaign was running from November 2013 to April 2015 with an atmospheric argon target and a reduced efficiency neutron veto due to internal contamination. However, an upper limit on the WIMP-nucleon cross section of 6.1×10−44 cm2 at 90% CL was obtained for a WIMP mass of 100 GeV/c2 and an exposure of (1422 ± 67) kg·d. At present DarkSide-50 started a 3 years run, intended to be background-free because the neutron veto was successfully recovered and underground argon replaced the atmospheric one. Additionally calibration campaigns for both the TPC and the neutron veto were completed. Thanks to the good perf...

The DarkSide physics program and its recent results

Il Nuovo Cimento C, 2016

Here, DarkSide (DS) at Gran Sasso underground laboratory is a direct Dark Matter search program b... more Here, DarkSide (DS) at Gran Sasso underground laboratory is a direct Dark Matter search program based on Time Projection Chambers (TPC) with liquid Argon from underground sources. The DarkSide-50 (DS-50) TPC, with 150 kg of Argon is installed inside active neutron and muon detectors. DS-50 has been taking data since November 2013 with Atmospheric Argon (AAr) and since April 2015 with Underground Argon (UAr), depleted in radioactive 39Ar by a factor ~1400. The exposure of 1422 kg d of AAr has demonstrated that the operation of DS-50 for three years in a background free condition is a solid reality, thanks to the superb performance of the Pulse Shape Analysis. The first release of results from an exposure of 2616 kg d of UAr has shown no candidate Dark Matter events. We have set the best limit for Spin-Independent elastic nuclear scattering of WIMPs obtained by Argon-based detectors, corresponding to a cross-section of 2 10–44 cm2 at a WIMP mass of 100 GeV. We present the detector des...

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Status and perspective of the DarkSide experiment at LNGS

The DarkSide experiment aims to perform a background-free direct search for dark matter with a du... more The DarkSide experiment aims to perform a background-free direct search for dark matter with a dual-phase argon TPC. The current phase of the experiment, DarkSide-50, is acquiring data at Laboratori Nazionali del Gran Sasso and produced the most sensitive limit on the WIMP-nucleon cross section ever obtained with a liquid argon target (2.0 × 10−44 cm2 for a WIMP mass of 100 GeV/c2 ). The future phase of the experiment will be a 20 t fiducial mass detector, designed to reach a sensitivity of ∼ 1 × 10−47 cm2 (at 1 TeV/c2 WIMP mass) with a backgroundfree exposure of 100 ty. This work contains a discussion of the current status of the DarkSide-50 WIMP search and of the results which are more relevant for the construction of the future detector.

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$Research paper thumbnail of JUNO Sensitivity on Proton Decay $p\to \bar\nu K^+$ Searches$

JUNO Sensitivity on Proton Decay $p\to \bar\nu K^+$ Searches

HAL (Le Centre pour la Communication Scientifique Directe), Dec 16, 2022

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Study of the primary cosmic ray composition around 1000 TeV with EAS-TOP and MACRO

Nuclear Physics B - Proceedings Supplements, 1996